## Mezzanines

Mezzanine is defined as being "an intermediate floor assembly between the floor and ceiling of any room or storey and includes an interior balcony".

### Building Height

Building Height means the number of storeys contained between the roof and the floor of the first storey.

The consideration of mezzanines as storeys is dependant on the area of mezzanine occupied space in relation to the total area of the room.  If the mezzanine is considered as a storey, then it must be taken into account when determining the height of a building. The reason that this consideration is important is because of the added and onerous requirements that can come with a ‘two’ storey building as opposed to one.

Mezzanine or ‘middle tier floors’ are considered as a single area regardless of number. This means that if one floor level in an area occupies 30% of the floor and another occupies 20%, then the mezzanine needs to be counted as a storey.

Why worry about whether the mezzanine is a storey or not?

Why not simply let the mezzanine be a storey?

For the purpose of determining building code requirements vis-à-vis fire protection and construction types, building height is measured in storeys, not feet or metres. The height of a building plays a pivotal role in a series of decisions that need to be made in terms of design and construction. The main criteria that change are the construction requirements and the fire ratings.

Figure 1                Mezzanine floor in relation to Building Height

### Building Size Determination

1.      Mezzanines are not considered to be storeys for the purpose of determining the building height if:

a.      the total area of the mezzanine floor does not exceed 10% of the suite in which it is located,

b.      the total area of the mezzanine floor does not exceed 10% of the storey in which it is located.

2.      Mezzanines are not considered to be storeys for the purpose of determining the building height if :

a.      the total area of the mezzanine floor in relation to the entire area of the room does not exceed 40% and,

b.      there are no visual obstructions more than 1070 mm (3 ft 6 in) above the floor.

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